Possible toxic water factor in coronary heart-disease.

Many reports indicate a significant negative correlation between death-rates for coronary heart-disease (C.H.D.) and water hardness. A reverse situation exists in the twin Kansas cities, U.S.A. Kansas City, Kansas, has water which is more than twice as hard as the softened water of Kansas City, Missouri, from the same source. Serum cholesterol and triglyceride levels were similar, but blood-pressure was higher in Kansas City, Kansas, and this correlated with higher serum-sodium, lower serum-potassium, and a tenfold higher serum-cadmium. Serum calcium and magnesium levels were higher in Kansas, while copper, chromium, cobalt, and zinc were higher in Missouri. The serum studies were con ducted on two matched groups of 260 adults from each of the sample cities. Hypertension may account for the reverse C.H.D. rate noted and be cadmium related.